Token

contract Token {
    mapping(address => uint256) balances;
    mapping(address => mapping(address => uint256)) allowed;
    uint256 _supply;
    event Transfer(address indexed _from, address indexed _to, uint256 _value);
    event Approval(address indexed _owner, address indexed _spender, uint256 _value);
    function transfer(address _to, uint256 _value) returns (bool) {
        if (balances[msg.sender] >= _value && _value > 0) {
            balances[msg.sender] -= _value;
            balances[_to] += _value;
            Transfer(msg.sender, _to, _value);
            return true;
        } else { return false; }
    }
    function transferFrom(address _from, address _to, uint256 _value) returns (bool) {
        if (balances[_from] >= _value && allowed[_from][msg.sender] >= _value && _value > 0) {
            balances[_to] += _value;
            Transfer(_from, _to, _value);
            balances[_from] -= _value;
            allowed[_from][msg.sender] -= _value;
            return true;
        } else { return false; }
    }
    function balanceOf(address _owner) constant returns (uint256) { return balances[_owner]; }
    function approve(address _spender, uint256 _value) returns (bool) {
        allowed[msg.sender][_spender] = _value;
        Approval(msg.sender, _spender, _value);
        return true;
    }
    function allowance(address _owner, address _spender) constant returns (uint256) { return allowed[_owner][_spender]; }
    function totalSupply() constant returns (uint256) { return _supply; }
}